The Scandinavian Defense (also known as the Center Counter in the USA) has one unique advantage compared to any other sharp line we've analyzed so far. Let's say you want to play the Latvian gambit (1.e4 e5 2. Nf3 f5). If your opponent plays the King's Gambit, Bishop Opening or any other move different from 2. Nf3, you can kiss your Latvian Gambit goodbye. This is not the case with the Scandinavian Defense. The only requirement here is that your opponent plays 1. e4 and then you play 1... d5. Bingo! You got your Scandinavian defense!
These days the most popular line of the Scandinavian amongst GMs is 2.exd5 Qxd5 3.Nc3 Qd6 which leads to a tough positional struggle in most of the cases. But what if you are looking for a street fight from the very first move? Then 2...Nf6!? is your move! This move turns the Scandinavian Defense into a real gambit since White can keep his extra pawn with the 3.c4 move. In return Black gets a very dangerous initiative as the next game shows:
Instead of 3.c4 White can play 3.d4 ignoring the d5 pawn and just try to finish his development. Even in this case Black retains attacking chances. The next game is a good example of Black's play in this case. I recommend that you analyze every move and look at the annotations since Black's play is pretty typical for this variation. Take note of how surprisingly quickly White's seemingly solid looking position was torn apart.
Another possible approach for Black after 3.d4 is to give White another chance to keep his extra pawn in return for a strong initiative. You don't see too often a 2500+ GM playing White and getting checkmated by move 13, but that's exactly what happened in the following game:
So, is there any hope for White in this line, or does the Scandinavian Defense simply refute the 1.e4 move? Sure White's play in the above mentioned games can be improved, but probably the most solid approach for White is just to ignore all the sacrifices and stick to his guns by finishing the development. Veselin Topalov is arguably one of the most theoretically prepared chess players of our time and he chose exactly this approach when facing GM Gata Kamsky. Black's mistake in this game was that instead of switching to positional play (I know this is a real hell for any gambiteer!) he kept playing too aggressively and got annihilated. Judge for yourself:
In conclusion I would like to add my usual advice. Since there is no way to analyze all possible lines of any opening in just one brief article, my goal is just to explain the main ideas, to demonstrate typical attacking patterns and to share the spirit of the opening. If you like it, I strongly recommend you to do your homework before you play it. The Scandinavian Defense is a unique opening that provides Black an opportunity to seize the initiative starting from move one! Many prominent players have trotted this opening out, so perhaps you should as well.
Good luck!